The present invention relates generally to the field of undo and redo operations, and more particularly to undo and redo operations based upon the content type affected by the operations.
Undo and redo is a function used daily in computer systems to undo the last operation performed or redo the last operation that was undone. Currently, a user can undo anything they have done by mistake. Alternatively, if a user deletes something or undoes something, they can redo that operation and have the content return to its previous form. Undo and redo perform operations in a last in first out (LIFO) manner. LIFO refers to the way items stored in some types of data structures are processed. By definition, in a LIFO-structure linear list, elements can be added or taken off from only one end, called the “top”. A LIFO structure can be illustrated with the example of a stack of trays; the last tray to be placed on top is also the first to be taken off the top. In other words, the last operation done, or placed on the top, is the first operation undone, or taken off the top.